#include "apue.h"

static void sig_quit(int);

int 
main(void) {
	sigset_t newmask, oldmask, pendmask;

	if (signal(SIGQUIT, sig_quit) == SIG_ERR) {
		err_sys("can't catch SIGQUIT");
	}

	sigemptyset(&newmask);
	sigaddset(&newmask, SIGQUIT);
	if (sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0) {
		err_sys("SIG_BLOCK error");
	}

	sleep(5);

	if (sigpending(&pendmask) < 0) {
		err_sys("sigpending error");
	}

	if (sigismember(&pendmask, SIGQUIT)) {
		printf("\nSIGQUIT pending\n");
	}

	if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0) {
		err_sys("SIG_SETMASK, error");
	}

	printf("SIGQUIT unblocked\n");

	sleep(5);
	exit(0);
}

static void 
sig_quit(int signo) {
	printf("caught SIGQUIT\n");

	if (signal(SIGQUIT, SIG_DFL) == SIG_ERR) {
		err_sys("can't reset SIGQUIT");
	}
}
